Environmental Distribution of Cyanobacteria and their Toxins in the Carraizo Reservoir, Puerto Rico.

摘要

Cyanobacteria and their toxins is a problem of actual concern. Although not well understood known, enough research is underway for explanation of this global phenomenon. At Puerto Rico, research in cyanobacteria is scarce; hence we decided to analyze the presence of cyanobacteria and their toxin at Carraizo Lake. For a period of 14 months, December 2008 to January 2010, 26 sampling sites were taken at Carraizo Lake for survey, surface and deep. Cyanobacteria microorganism and their toxins (microcystins) were analyzed and identified. The influence of different chemical, physical, biological and limnological parameter were analyzed to examine the effect on cyanobacteria growth and toxin production in the presence of dominants Spp, Spp distribution, Spp biodiversity, Spp richness and toxin producer. In addition LD50 was evaluated for some cyanobacteria spp that was found at water reservoirs like Microcystis, Nostoc, Nodularia, Anabaena, Chroococcus Gloeocapsa, and Oscillatoria. Some of the variable that was taken in consideration was the presence of nutrient like phosphate and nitrate, temperature, deep, photic zone, rainfall; season, water flow, extreme rainfall, suspended particle, daily rainfalls, Spp competent, erosion, between others. As a consequence of our research 52 spp of cyanobacteria was identified, some of them can be new species. There was other cyanobacteria that was present but not was able to be cultivated. Twelve cyanobacteria chemical species that belonged to the microcystins group was isolated and identified using LC/MS MS Time of Flight. Hepatotoxic microcystins LR and other, were identified and their distribution in Carraizo Lake was demonstrated. It was found that some cyanobacteria species have a strong correlation and is influence by the deep, extreme rainfall; runoff and they show a systematic succession process through a water column. We demonstrate that cyanobacteria communities are very dynamic through water surface and deeps zones. A very impact situation is demonstrated at Carraizo waters columns, and is the extreme concentration and high level and concentration of nutrient that are affected by water runoff from the watershed to the river to the water reservoirs. These situations demonstrate that Carraizo Lake is a night hypertrophic water reservoirs. Those characteristics joint to the absent of a water quality standard from the Department of Public Health from the Federal and Stated regulatory Agency for the presences of cyanotoxins enhance the high risk that exit for human, domestic and wild life animal.